Method and apparatus for treating PCB-containing soil

Abstract

A method and apparatus for treating polychlorinated biphenyl (PCB) contaminated soil includes providing a contaminated soil having PCBs therein and treating the soil with elemental zinc powder. The elemental zinc powder reacts with the PCBs in the contaminated soil to at least partially dechlorinate the PCB component of the soil. Also provide are means for treating the PCB contaminated soil including grinding means for achieving a preferred size range for the soil and mixing means to provide intimate contact between the contaminated soil and elemental zinc powder. The method may be practice in-situ such that the PCB contaminated soil is treated at a soil site containing the PCB contaminants.

We claim: 
     
       1. A method of treating polychlorinated biphenyl-containing soil comprising: a) providing a moistened soil containing an amount of polychlorinated biphenyls therein;   b) adding an amount of elemental zinc in powder form to said moistened soil as the sole material added thereto;   c) mixing said elemental zinc in powder form with said moistened soil to provide a mixture thereof; and   d) reacting said elemental zinc in powder form with said polychlorinated biphenyls at ambient temperature and pressure over a predetermined period of time, said elemental zinc powder being in an amount effective to at least partially dechlorinate said polychlorinated biphenyls in said moistened soil.   
     
     
       2. The method of claim 1 wherein said providing comprises providing an in-situ soil site having said moistened soil containing an amount of polychlorinated biphenyls therein. 
     
     
       3. The method of claim 2 further comprising comminuting said moistened soil prior to said adding. 
     
     
       4. The method of claim 3 wherein said moistened soil has a particle size generally less than 3/16 inch. 
     
     
       5. The method of claim 1 wherein said providing further comprises removing said moistened soil from a soil site prior to said adding. 
     
     
       6. The method of claim 5 further comprising adding an amount of water to provide said moistened soil prior to said reacting. 
     
     
       7. The method of claim 6 wherein said adding and mixing are performed in a mixing means. 
     
     
       8. The method of claim 7 further comprising returning said moistened soil to said soil site. 
     
     
       9. The method of claim 1 wherein said providing comprises adding an amount of water to provide said moistened soil for said reacting. 
     
     
       10. The method of claim 1 wherein said predetermined period of time exceeds 7 days.